2018-10-10 22:03:03 +00:00
|
|
|
|
---
|
|
|
|
|
id: 5900f3851000cf542c50fe98
|
|
|
|
|
challengeType: 5
|
|
|
|
|
videoUrl: ''
|
2020-10-01 15:54:21 +00:00
|
|
|
|
title: 问题25:1000位斐波纳契数
|
2018-10-10 22:03:03 +00:00
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
## Description
|
|
|
|
|
<section id="description"> Fibonacci序列由递归关系定义: <div style="padding-left: 4em;"> F <sub>n</sub> = F <sub>n-1</sub> + F <sub>n-2</sub> ,其中F <sub>1</sub> = 1且F <sub>2</sub> = 1。 </div>因此,前12个学期将是: <div style="padding-left: 4em; display: inline-grid; grid-template-rows: auto; row-gap: 7px;"><div> F <sub>1</sub> = 1 </div><div> F <sub>2</sub> = 1 </div><div> F <sub>3</sub> = 2 </div><div> F <sub>4</sub> = 3 </div><div> F <sub>5</sub> = 5 </div><div> F <sub>6</sub> = 8 </div><div> F <sub>7</sub> = 13 </div><div> F <sub>8</sub> = 21 </div><div> F <sub>9</sub> = 34 </div><div> F <sub>10</sub> = 55 </div><div> F <sub>11</sub> = 89 </div><div> F <sub>12</sub> = 144 </div></div>第12个学期F <sub>12</sub>是第一个包含三位数的术语。 Fibonacci序列中包含<var>n个</var>数字的第一项的索引是多少? </section>
|
|
|
|
|
|
|
|
|
|
## Instructions
|
|
|
|
|
<section id="instructions">
|
|
|
|
|
</section>
|
|
|
|
|
|
|
|
|
|
## Tests
|
|
|
|
|
<section id='tests'>
|
|
|
|
|
|
|
|
|
|
```yml
|
|
|
|
|
tests:
|
|
|
|
|
- text: <code>digitFibonacci(5)</code>应该返回21。
|
2020-02-17 16:40:55 +00:00
|
|
|
|
testString: assert.strictEqual(digitFibonacci(5), 21);
|
2018-10-10 22:03:03 +00:00
|
|
|
|
- text: <code>digitFibonacci(10)</code>应该返回45。
|
2020-02-17 16:40:55 +00:00
|
|
|
|
testString: assert.strictEqual(digitFibonacci(10), 45);
|
2018-10-10 22:03:03 +00:00
|
|
|
|
- text: <code>digitFibonacci(15)</code>应该返回69。
|
2020-02-17 16:40:55 +00:00
|
|
|
|
testString: assert.strictEqual(digitFibonacci(15), 69);
|
2018-10-10 22:03:03 +00:00
|
|
|
|
- text: <code>digitFibonacci(20)</code>应该返回93。
|
2020-02-17 16:40:55 +00:00
|
|
|
|
testString: assert.strictEqual(digitFibonacci(20), 93);
|
2018-10-10 22:03:03 +00:00
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
</section>
|
|
|
|
|
|
|
|
|
|
## Challenge Seed
|
|
|
|
|
<section id='challengeSeed'>
|
|
|
|
|
|
|
|
|
|
<div id='js-seed'>
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
function digitFibonacci(n) {
|
|
|
|
|
// Good luck!
|
|
|
|
|
return n;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
digitFibonacci(20);
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
</section>
|
|
|
|
|
|
|
|
|
|
## Solution
|
|
|
|
|
<section id='solution'>
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
// solution required
|
|
|
|
|
```
|
2020-08-13 15:24:35 +00:00
|
|
|
|
|
|
|
|
|
/section>
|